A three-component synthesis of functionalized ketenimines by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of 2-quinolinol

Article abstract of DOI:10.2298/JSC100218011M

The 1:1 reactive intermediates generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates were trapped by 2-quinolinol to yield highly functionalized ketenimines and, in some cases, minor amounts of 1-azabuta-1,3-dienes.

Full text of DOI:10.2298/JSC100218011M

J. Serb. Chem. Soc. 76 (1) 13–20 (2011)
JSCS–4094
UDC 547.48+547.467+547.313+
547.239+547.421:542.9
Original scientific paper
A three-component synthesis of functionalized ketenimines by
the reaction of alkyl isocyanides and dialkyl acetylene-
dicarboxylates in the presence of 2-quinolinol
1
2
3
1
*
BITA MOHTAT , HOORIEH DJAHANIANI , ISSA YAVARI and KOBRA NADERI
1Chemistry Department, Islamic Azad University, Karaj Branch, Karaj, 2Chemistry
Department, Islamic Azad University, East Branch, Qiamdasht, Tehran and 3Chemistry
Department, Islamic Azad University, Science and Research Branch, Tehran, Iran
(Received 18 February, revised 21 June 2010)
Abstract: The 1:1 reactive intermediates generated by the addition of alkyl
isocyanides to dialkyl acetylenedicarboxylates were trapped by 2-quinolinol to
yield highly functionalized ketenimines and, in some cases, minor amounts of
1-azabuta-1,3-dienes.
Keywords: ketenimines; 1-azadienes; alkyl isocyanides; acetylenic esters; NH-
-acids; multi-component reaction.
INTRODUCTION
Ketenimines are important reactive intermediates that occur as transient
1
compounds in many thermal and photochemical reactions. There has been in-
2
3,4
tense interest in their reactions, such as cycloaddition, nucleophilic and elec-
5
trophilic addition. They have also found widespread use as reactive starting
materials for the formation of four-, five-, and six-membered heterocyclic ring
5–7
systems.
Methods for the synthesis of ketenimines have been extensively re-
8
viewed. The addition of nucleophilic carbenes, such as isocyanides, to dialkyl
9
acetylenedicarboxylates was investigated in detail. The trapping of the 1:1 in-
termediate formed between dialkyl acetylenedicarboxylates and isocyanides with
10–14
OH, NH, and CH acids has been widely studied.
In continuation of our in-
15–18
terest in the application of isocyanides in multi-component reactions, MCR,
an efficient synthesis of ketenimine 4 from alkyl isocyanides 1 and dialkyl ace-
tylenedicarboxylates 2 in the presence of a strong NH-acid, such as quinolin-2-ol,
is reported herein. In some cases, minor amounts (13–25 %) of 1-azadienes 5
were obtained (Scheme 1).
*Corresponding author. E-mail: B.mohtat@jooyan.org
doi: 10.2298/JSC100218011M
13
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14
MOHTAT et al.
Scheme 1. Typical procedure for the synthesis of compounds 4 and 5.
RESULTS AND DISCUSSION
The reaction of alkyl isocyanides 1 with acetylenic esters 2 in the presence
of an NH-acid, such as quinolin-2-ol, afforded the isomeric highly functionalized
ketenimines 4 in fairly good yields.
The structures of 4 and 5 were deduced from their elemental analyses, mass
1
13
spectrometric data, and their H- and C-NMR, DEPT and IR spectral data,
given below.
Dimethyl 2-(cyclohexylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succinate
(4a). Yellow oil; yield: 63 %; Anal. Calcd. for C H N O : C, 66.65; H, 6.10;
22 24
2 5
–1
N, 7.07 %. Found: C, 66.70; H, 6.07; N, 7.05 %. IR (KBr, cm ): 2077
(–C=C=N stretching), 1745 (–C=O stretching of –COOR group), 1651 (–C=O
1
stretching of amide group). H-NMR (300 MHz, CDCl , δ / ppm): 1.20–2.07
3
(10H, m, 5 CH ), 3.72 (6H, s, 2 OCH ), 3.86 (1H, m, H–CN), 6.17 (1H, s, CH),
2
3
6.64 (1H, d, aromatic, J = 9.4 Hz, CH), 7.26 (1H, t, aromatic, J = 7.5 Hz, CH),
7.58 (1H, d, aromatic, J = 7.5 Hz, CH), 7.62 (1H, t, aromatic, J = 8.6 Hz, CH),
7.72 (1H, d, aromatic, J = 9.4 Hz, CH), 7.86 (1H, d, aromatic, J = 8.6 Hz, CH).
13
C-NMR (75.4 MHz, CDCl , δ / ppm): 24.4 (CH ), 25.0 (CH ), 25.6 (CH )
3
2
2
2
33.0 (CH ), 33.4 (CH ), 52.0 (OCH ), 53.2 (OCH ), 55.4 (C–H), 59.7 (C=C=N),
2
2
3
3
60.8 (C–N), 115.3 (CH=), 121.4 (CH=), 122.8 (CH=), 123.0 (CH=), 129.3
(CH=), 131.4 (CH=), 139.7 (C=), 140.6 (C=), 162.5 (C=O), 164.8 (C=O), 168.8
(C=O), 171.5 (C=C=N). DEPT (125.7 MHz, CDCl , δ / ppm): 24.4 (CH ), 25.7
3
2
(CH ), 25.9 (CH ) 32.8 (CH ), 33.4 (CH ), 52.0 (OCH ), 53.2 (OCH ), 55.4 (C–H),
2
2
2
2
3
3
60.8 (C–N), 115.3 (CH=), 121.4 (CH=), 122.9 (CH=), 123.4 (CH=), 129.3
(=CH), 131.4 (=CH), 139 (C=), 140.5 (C=), 160.4 (C=O), 162.7 (C=O), 167.4
+
(C=O), 170.6 (C=C=N). MS (m/z, (relative abundance, %)): 396 (M , 18), 270
(24), 237 (32), 171 (58), 156 (39), 145 (47), 83 (100), 55 (58), 41(56).
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SYNTHESIS OF FUNCTIONALIZED KETENIMINES
15
Dimethyl 2-[(E)-(cyclohexylimino)(2-oxo-1(2H)-quinolinyl)methyl]but-2-ene-
dioate (5a). Yellow oil; yield: 26 %; Anal. Calcd. for C H N O : C, 66.65; H,
22 24
2 5
–1
6.10; N, 7.07 %. Found: C, 66.69; H, 6.13; N, 7.02 %. IR (KBr, cm ): 1732
(–C=O stretching of –COOR group), 1668 (–C=O stretching of amide group),
1
1594 (–C=N stretching of imine group). H-NMR (300 MHz, CDCl , δ / ppm):
3
1.10–1.90 (10H, m, 5 CH ), 3.10 (1H, m, HC–N), 3.67 (3H, s, OCH ), 3.95 (3H,
2
3
s, OCH ), 5.71 (1H, s, CH), 6.70 (1H, d, aromatic, J = 9.6 Hz, CH), 7.02 (1H, d,
3
aromatic, J = 8.4 Hz, CH), 7.27 (1H, t, aromatic, J = 7.8 Hz, CH), 7.50 (1H, t,
aromatic, J = 8.4 Hz, CH), 7.62 (1H, d, aromatic, J = 7.8 Hz, CH), 7.81 (1H, d,
13
aromatic, J = 9.6 Hz, CH). C-NMR (75.4 MHz, CDCl , δ / ppm): 23.4 (CH ),
3
2
23.5 (CH ), 25.5 (CH ) 32.04 (CH ), 32.4 (CH ), 52.3 (OCH ), 52.7 (OCH ),
2
2
2
2
3
3
60.9 (C–N), 114.5 (CH=), 119.8 (CH=), 121.4 (CH=), 122.9 (CH=), 123.4
(CH=), 128.9 (C=), 131.4 (CH=), 137.5 (CH=), 141.0 (C=), 144.3 (C=), 144.8
(C=N), 160.1 (C=O), 164.6(C=O), 165.8 (C=O). MS (m/z, (relative abundance,
+
%)): 396 (M , 10), 280 (37), 227 (100), 170 (55), 83 (45), 55 (38).
Diethyl 2-(cyclohexylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succinate
(4b). Yellow oil; yield: 71 %; Anal. Calcd. for C H N O : C, 67.91; H, 6.65; N,
24 28
2 5
–1
6.60 %. Found: C, 67.82; H, 6.68; N, 6.69 %. IR (KBr, cm ): 2093 (–C=C=N
stretching), 1741 (–C=O stretching of –COOR group), 1672 (–C=O stretching of
1
amide group). H-NMR (300 MHz, CDCl , δ / ppm): 1.11–1.99 (10H, m, 5
3
CH ), 1.19 (3H, t, J = 7.1 Hz, CH –CH ), 1.23 (3H, t, J = 7.1 Hz, CH –CH ),
2
2
3
2
3
3.89 (1H, m, HC–N), 4.19 (2H, q, J = 7.1 Hz, OCH –CH ), 4.29 (2H, m, OCH –
2
3
2
CH ), 6.13 (1H, s, CH), 6.60 (1H, d, aromatic, J = 9.4 Hz, CH), 7.24 (1H, t,
3
aromatic, J = 7.8 Hz, CH), 7.56–7.60 (2H, m, aromatic, 2 CH), 7.70 (1H, d,
13
aromatic, J = 9.4 Hz, CH), 7.88 (1H, d, aromatic, J = 8.6 Hz, CH). C-NMR
(75.4 MHz, CDCl , δ / ppm): 14.0 (CH ), 14.4 (CH ), 23.8 (CH ), 25.3 (2 CH ),
3
3
3
2
2
32.9 (2 CH ), 55.1 (C–H), 59.7 (C=C=N), 60.2 (OCH ), 60.3 (OCH ), 61.9 (C–N),
2
2
2
115.0 (=CH), 120.9 (=CH), 121.0 (=CH), 122.3 (=CH), 128.9 (=CH), 130.9
(=CH), 139.4 (C=), 140.2 (C=), 160.2 (C=O), 162.1 (C=O), 167.9 (C=O), 170.8
+
(C=C=N). MS (m/z, (relative abundance, %)): 424 (M , 7), 341 (76), 280 (71),
144 (100), 97 (38), 29 (44).
Diethyl 2-[(E)-(cyclohexylimino)(2-oxo-1(2H)-quinolinyl)methyl]but-2-ene-
dioate (5b). Yellow oil; yield: 19 %; Anal. Calcd. for C H N O : C, 67.91; H,
24 28
2 5
–1
6.65; N, 6.60 %. Found: C, 67.88; H, 6.68; N, 6.63 %. IR (KBr, cm ): 1741 (–
C=O stretching of –COOR group), 1672 (–C=O stretching of amide group), 1590
1
(–C=N stretching of imine group); H-NMR (300 MHz, CDCl , δ / ppm): 1.06–
3
–1.97 (10H, m, 5 CH ), 1.32 (3H, t, J = 7.1 Hz, CH –CH ), 1.40 (3H, t, J = 7.1 Hz,
2
2
3
CH –CH ), 3.09 (1H, m, H–CN), 4.15 (2H, q, J = 7.1 Hz, OCH –CH ), 4.44
2
3
2
3
(2H, m, OCH –CH ), 5.71 (1H, s, CH), 6.70 (1H, d, aromatic, J = 9.6 Hz, CH),
2
3
7.05 (1H, d, aromatic, J = 8.5 Hz, CH), 7.29 (1H, t, aromatic, J = 8.5 Hz, CH),
7.50 (1H, t, aromatic, J = 7.5 Hz, CH), 7.78 (1H, d, aromatic, J = 7.8 Hz, CH),
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MOHTAT et al.
13
7.80 (1H, d, aromatic, J = 9.6 Hz, CH). C-NMR (75.4 MHz, CDCl , δ / ppm):
3
13.6 (CH ), 13.9 (CH ), 23.5 (CH ), 25.1 (CH ), 25.5 (CH ), 32.4 (CH ), 32.6
3
3
2
2
2
2
(CH ), 60.7 (C–N), 61.3 (OCH ), 61.7 (OCH ), 114.7 (=CH), 119.8 (=CH),
2
2
2
121.5 (=CH), 123.2 (=CH), 123.4 (=CH), 128.8 (C=), 131.3 (=CH), 137.5 (C=),
141 (=CH), 144.3 (C=), 144.6 (C=N), 163.8 (C=O), 164.0 (C=O), 165.3 (C=O).
+
MS (m/z, (relative abundance, %)): 424 (M , 7), 280 (31), 253 (56), 227 (100),
171 (48), 83 (41), 29 (35).
Di-tert-butyl
2-(cyclohexylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)suc-
cinate (4c). Yellow oil; yield: 55 %; Anal. Calcd. for C H N O : C, 69.98; H,
28 36
2 5
–1
7.55; N, 5.83 %. Found; C, 69.51; H, 7.60; N, 5.79 %. IR (KBr, cm ): 2073
(–C=C=N stretching), 1721 (–C=O stretching of –COOR group), 1673 (–C=O
1
stretching of amide group). H-NMR (300 MHz, CDCl , δ / ppm): 1.06–2.01
3
(10H, m, 5 CH ), 1.41 (9H, s, C(CH ) ), 1.46 (9H, s, C(CH ) ), 3.85 (1H, m,
2
3 3
3 3
H–CN), 6.04 (1H, s, CH), 6.64 (1H, d, aromatic, J = 9.2 Hz, CH), 7.28 (1H, t,
aromatic, J = 7.5 Hz, CH), 7.55–7.62 (2H, m, aromatic, 2 CH), 7.69 (1H, d,
13
aromatic, J = 9.4 Hz, CH), 7.82 (1H, d, aromatic, J = 8.4 Hz, CH). C-NMR
(75.4 MHz, CDCl , δ / ppm): 24.3 (CH ), 25.1 (CH ), 25.8 (CH ), 28.2 (C(CH ) ),
3
2
2
2
3 3
28.9 (C(CH ) ), 33.46 (2 CH ), 57.5 (C–H), 62.5 (C=C=N), 68.9 (C–N), 80.5
3 3
2
(C–O), 82.3 (C–O), 115.7 (CH), 121.6 (=CH), 122.5 (=CH), 129.1 (=CH), 130.2
(=CH), 131.1 (=CH), 139.9 (C=), 140.2 (C=), 162.4 (C=O), 165.1 (C=O), 167.9
+
(C=O), 176.5 (C=C=N). MS (m/z, (relative abundance, %)): 480 (M , 11), 336
(47), 202 (74), 158 (100), 122 (36), 83 (49), 57 (100).
Di-tert-butyl 2-[(E)-(cyclohexylimino)(2-oxo-1(2H)-quinolinyl)methyl] but-2-
-enedioate (5c). Yellow oil; yield: 16 %; Anal. Calcd. for C H N O : C, 69.98;
28 36
2 5
–1
H, 7.55; N, 5.83 %. Found; C, 69.94; H, 7.58; N, 5.79 %. IR (KBr, cm ): 1732
(–C=O stretching of –COOR group), 1660 (–C=O stretching of amide group),
1
1595 (–C=N stretching of imine group). H-NMR (300 MHz, CDCl , δ / ppm):
3
1.08–2.00 (10H, m, 5 CH ), 1.42 (9H, s, C(CH ) ), 1.60 (9H, s, C(CH ) ), 3.08
2
3 3
3 3
(1H, m, H–CN), 5.70 (1H, s, CH), 6.72 (1H, d, aromatic, J = 9.5 Hz, CH), 7.15
(1H, d, aromatic, J = 8.2 Hz, CH), 7.28 (1H, t, aromatic, J = 8.2 Hz , CH), 7.50
(1H, t, aromatic, J = 7.4 Hz, CH), 7.62 (1H, d, aromatic, J = 7.4 Hz, CH), 7.81
13
(1H, d, aromatic, J = 9.5 Hz, CH). C-NMR (75.4 MHz, CDCl , δ / ppm): 23.8
3
(CH ), 23.9 (CH ), 25.9 (CH ), 28.3 (C(CH ) ), 28.5 (C(CH ) ), 32.4 (CH ),
2
2
2
3 3
3 3
2
32.6 (CH ), 60.9 (C–N), 82.1 (C–O), 83.0 (C–O), 115.4 (=CH), 120.2 (=CH),
2
121.9 (=CH), 123.6 (=CH), 125.0 (=CH), 129.0 (=CH), 131.7 (C=), 138.3 (=CH),
141.2 (C=), 144.0 (C=), 144.9 (C=N), 160.6 (C=O), 163.8 (C=O), 165.4 (C=O).
+
MS (m/z, (relative abundance, %)):480 (M , 11), 336 (37), 253 (48), 227 (100),
144 (45), 83 (47), 57 (35).
Dimethyl 2-(tert-butylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succinate
(4d). Yellow oil; yield: 87 %; Anal. Calcd. for C H N O : C, 64.85; H, 5.99; N,
20 22
2 5
–1
7.56 %. Found: C, 64.89; H, 5.94; N, 7.60 %. IR (KBr, cm ): 2079 (–C=C=N
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SYNTHESIS OF FUNCTIONALIZED KETENIMINES
17
stretching), 1750 (–C=O stretching of –COOR group), 1670 (–C=O stretching of
1
amide group). H-NMR (300 MHz, CDCl , δ / ppm): 1.43 (9H, s, C(CH ) ), 3.70
3
3 3
(3H, s, –OCH ), 3.72 (3H, s, –OCH ), 6.12 (1H, s, CH), 6.63 (1H, d, aromatic,
3
3
J = 9.4 Hz, CH), 7.24 (1H, t, aromatic, J = 7.5 Hz, CH), 7.51–7.62 (2H, m,
aromatic, 2 CH), 7.70 (1H, d, aromatic, J = 8.9 Hz, CH), 7.80 (1H, d, aromatic,
13
J = 8.6 Hz, CH). C NMR (75.4 MHz, CDCl , δ / ppm): 30.0 (C(CH ) ), 51.7
3
3 3
(OCH ), 52.8 (OCH ), 54.8 (C–H), 60.9 (C=C=N), 68.1 (C–N), 114.8 (=CH),
3
3
121.1 (=CH), 122.5 (=CH), 128.9 (=CH), 131.0 (=CH), 132.4 (=CH), 139.2
(C=), 140.3 (C=), 162.0 (C=O), 167.7 (C=O), 168.3 (C=O), 171.0 (C=C=N). MS
+
(m/z, (relative abundance, %)):370 (M , 4), 313 (31), 226 (29), 143 (85), 57
(100), 41 (34).
Diethyl 2-(tert-butylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succinate (4e).
Yellow powder; yield: 73 %; m.p. 93–97 °C; Anal. Calcd. for C H N O : C,
22 26
2 5
–1
68.71; H, 7.56; N, 6.14; found: C, 68.73; H, 7.50; N, 6.12. IR (KBr, cm ): 2073
(–C=C=N stretching), 1747 (–C=O stretching of –COOR group), 1646 (–C=O
1
stretching of amide group). H-NMR (300 MHz, CDCl , δ / ppm): 1.18 (3H, t,
3
J = 7.1 Hz, CH –CH ), 1.24 (3H, t, J = 7.1 Hz, CH –CH ), 1.43 (9H, s,
2
3
2
3
C(CH ) ), 4.20 (2H, q, J = 7.1 Hz, OCH –CH ), 4.29 (2H, m, OCH –CH ), 6.09
3 3
2
3
2
3
(1H, s, CH), 6.63 (1H, d, aromatic, J = 9.4 Hz, CH), 7.24 (1H, t, aromatic, J = 7.8
Hz, CH), 7.51–7.56 (2H, m. aromatic, 2 CH), 7.70 (1H, d, aromatic, J = 9.4 Hz,
13
CH), 7.83 (1H, d, aromatic, J = 8.6 Hz, CH). C-NMR (75.4 MHz, CDCl , δ /
3
/ ppm): 14.1 (CH ), 14.3 (CH ), 30.1 (C(CH ) ), 51.9 (C–H), 54.8 (C=C=N),
3
3
3 3
60.3 (C–N), 61.9 (OCH ), 62.2 (OCH ), 114.9 (=CH), 121.0 (=CH), 122.4
2
2
(=CH), 128.9 (=CH), 130.7 (=CH), 133.7 (=CH), 136.6 (C=), 139.4 (C=), 162.0
(C=O), 164.8 (C=O), 167.8 (C=O), 170.7 (C=C=N). MS (m/z, (relative
+
abundance, %)): 398 (M , 21), 342 (57), 269 (50), 254 (61), 223 (42), 195 (31),
145 (100), 57 (76), 41(42).
Di-tert-butyl 2-(tert-butylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succi-
nate (4f). Yellow powder; yield: 79 %; m.p. 94–98 °C; Anal. Calcd. for
C H N O : C, 68.70; H, 7.54; N, 6.16 %. Found: C, 68.73; H, 7.50; N, 6.12 %.
26 34
2 5
–1
IR (KBr, cm ): 2073 (–C=C=N stretching), 1743 (–C=O stretching of –COOR
group), 1666 (–C=O stretching of amide group). H-NMR (300 MHz, CDCl , δ /
1
3
/ ppm): 1.40 (18H, s, 2 C(CH ) ), 1.46 (9H, s, C(CH ) ), 5.99 (1H, s, CH), 6.63
3 3
3 3
(1H, d, aromatic, J = 9.4 Hz, CH), 7.22 (1H, t, aromatic, J = 7.4 Hz, CH), 7.55–
–7.60 (2H, m, aromatic, 2 CH), 7.67 (1H, d, aromatic, J = 9.4 Hz, CH), 7.75 (1H,
13
d, aromatic, J = 8.6 Hz, CH). C-NMR (75.4 MHz, CDCl , δ / ppm): 27.8
3
(C(CH ) ), 28.4 (C(CH ) ), 30.0 (C(CH ) ), 51.6 (C–H), 55.3 (C=C=N), 61.7
3 3
3 3
3 3
(C–N), 80.0 (C–O), 81.9 (C–O), 115.0 (CH=), 120.8 (CH=), 121.2 (CH=), 122.1
(CH=), 128.7 (CH=), 130.8 (CH=), 139.6 (C=), 139.5 (C=), 161.7 (C=O), 161.9
(C=O), 166.7 (C=O), 169.5 (C=C=N). MS (m/z, (relative abundance, %)): 454
+
(M , 2), 310 (24), 254 (23), 198 (35), 145 (82), 57 (100), 41 (30).
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MOHTAT et al.
1
The H-NMR spectrum of 4a exhibited three sharp lines for methoxy (δ 3.72
and 3.86 ppm) and methine (δ 6.17 ppm) protons. The cyclohexyl and quinolinol
13
moiety appeared at δ 1.20–2.07 ppm and 6.63–7.80 ppm. The C-NMR spec-
trum of 4a exhibited distinct resonances in agreement with the proposed struc-
ture. The DEPT spectrum of 4a exhibited fifteen sharp lines in agreement with
dimethyl 2-(cyclohexylcarbonimidoyl)-3-(2-oxo-1(2H)-quinolinyl)succinate. Par-
1
tial assignments of these resonances are given above. The H-NMR spectra of
4b–f are similar to that of 4a, except for the signals of the cyclohexyl and ester
1
moiety. The H-NMR spectrum of 5a displayed sharp signals for the methoxy (δ
13
3.67 and 3.95 ppm), and vinyl (δ 5.71 ppm) protons. The C-NMR spectrum of
5a exhibited distinct resonances in agreement with dimethyl 2-[(E)-(cyclohexyl-
imino)(2-oxo-1(2H)-quinolinyl)methyl]but-2-enedioate. A partial assignment of
these resonances is given above. The structural assignments of 5a–c made on the
basis of their NMR spectra were supported by their IR spectra. Of special interest
–1
is the strong ketenimine absorption band at about 2079 cm . Based on the well-
19–22
established chemistry of isocyanides,
it is reasonable to assume that 4 and 5
result from an initial addition of the alkyl isocyanide to the acetylenic ester and
subsequent protonation of the 1:1 adduct by the NH-acid. Then, the positively
charged ion 7 can be attacked at two positions by the nitrogen atom of the anion
of the NH-acid. Conjugate addition produces the ketenimines 4 and direct
addition leads to the 1-azadienes 5 (Scheme 2).
Scheme 1. A possible mechanism for the preparation of 4 and 5.
EXPERIMENTAL
Melting points were measured on an Electrothermal 9100 apparatus. Elemental analyses
for C, H, and N were performed using a Heraeus CHNO-Rapid analyzer. The IR spectra were
1
measured on a Shimadzu IR-460 spectrometer. The H- and 13C-NMR spectra were recorded
on a Bruker DRX-300 Avance instrument with CDCl3 as the solvent at 300 and 75 MHz,
respectively. The mass spectra were recorded on a Finnigan-Matt 8430 mass spectrometer
operating at an ionization potential of 70 eV. The alkyl isocyanides, dialkyl acetylenedi-
caboxylates and 2-quinolinol were obtained from Fluka and were used without further pu-
rification.
Typical procedure for the synthesis of ketenimines and 1-azadienes (4 and 5)
To a stirred solution of dialkyl acetylenedicarboxylate (2 mmol) and alkyl isocyanide (2
mmol) in 10 mL of CH2Cl2, 2-quinolinol (2 mmol) was added dropwise at 0 °C over 10 min.
The reaction mixture was then allowed to warm to room temperature and stand for 24 h. The
solvent was removed under reduced pressure and the residual solid was recrystallized from
diethyl ether. The oily products were purified by preparative TLC on silica gel (Merck silica
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SYNTHESIS OF FUNCTIONALIZED KETENIMINES
19
gel DC-Fertigplatten 60/Kieselguhr F254) 20 cm×20 cm plates using n-hexane-AcOEt (2:1)
as the eluent.
CONCLUSIONS
In conclusion, a method for the preparation of highly functionalized keten-
imines and 1-azadienes has once more been demonstrated. The present method
carries the advantage that not only is the reaction performed under neutral con-
ditions, but also the starting materials and reagents can be mixed without any
activation or modification.
И З В О Д
ТРОКОМПОНЕНТНА СИНТЕЗА ФУНКЦИОНАЛИЗОВАНИХ КЕТЕНИМИНА
ДОБИЈЕНИХ РЕАКЦИЈОМ АЛКИЛ-ИЗОЦИЈАНИДА И ДИАЛКИЛ-АЦЕ-
ТИЛЕНДИКАРБОКСИЛАТА У ПРИСУСТВУ 2-ХИНОЛИНОЛА
BITA MOHTAT1, HOORIEH DJAHANIANI2, ISSA YAVARI3 и KOBRA NADERI1
1Chemistry Department, Islamic Azad University, Karaj Branch, Karaj, 2Chemistry Department, Islamic Azad
University, Tehran Shargh Branch, Tehran и 3Chemistry Department, Islamic Azad University,
Science and Research Branch, Tehran, Iran
Смеша интермедијера, добијених у односу 1:1 адицијом алкил-изоцијанида на диалкил-
-ацетилендикарбоксилате, трапована је 2-хинолином, и као производ су добијени функцио-
нализовани кетенимини у високом приносу, а у неким примерима добијене су мале количине
1-азабута-1,3-диена.
(Примљено 18. фебруара, ревидирано 21. јуна 2010)
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